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sysfs: Add crash_notes_size to export percpu note size

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For percpu notes, we are exporting only address and not size. So
the userspace tool kexec-tools is putting an upper limit of 1024
and putting the value in p_memsz and p_filesz fields. So the patch
add the new sysfile crash_notes_size to export the exact percpu
note size and let the kexec-tools parse it intead of using 1024.

The idea came from Vivek Goyal. And a later patch will be sent to
kexec-tools to let it parse the size.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Zhang Yanfei 2013-03-28 16:15:35 +08:00 • committed by Greg Kroah-Hartman
commit eca4549f57
1 changed files with 14 additions and 0 deletions
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14
drivers/base/cpu.c
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@ -132,6 +132,17 @@ static ssize_t show_crash_notes(struct device *dev, struct device_attribute *att
return rc;
}
static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
static ssize_t show_crash_notes_size(struct device *dev,
struct device_attribute *attr,
char *buf)
{
ssize_t rc;
rc = sprintf(buf, "%lu\n", sizeof(note_buf_t));
return rc;
}
static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
#endif
/*
@ -259,6 +270,9 @@ int __cpuinit register_cpu(struct cpu *cpu, int num)
#ifdef CONFIG_KEXEC
if (!error)
error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
if (!error)
error = device_create_file(&cpu->dev,
&dev_attr_crash_notes_size);
#endif
return error;
}